A bone density (DEXA) scan takes about 10 to 30 minutes.
Time
A DEXA bone density scan takes about 10 to 30 minutes. You lie on a table while a scanner arm passes over the hip and spine.
Radiation
Very low, less than a chest X-ray, about 0.001 mSv.
Preparation
Wear loose clothes with no metal. Don’t take calcium supplements for 24 hours before.
Results
The T-score compares you with a healthy young adult. -1.0 or above is normal, -1.0 to -2.5 is low bone mass (osteopenia), -2.5 or below is osteoporosis.
Who needs one
Women 65 and older, postmenopausal women with risk factors and men over 70 (USPSTF and National Osteoporosis Foundation).
Cost
$100 to $250 without insurance.
Time
A bone density test, also called a DEXA or DXA scan, takes about 10 to 30 minutes. Scanning the hip and lower spine typically takes 10 to 15 minutes, and you lie on a padded table while an arm passes over your body. You must stay still for the images. The visit is usually short, with the appointment lasting about 30 to 45 minutes including check-in.
Radiation
A DEXA scan uses very low-dose X-rays, about 1/10 of a chest X-ray, or about 0.001 millisievert, which is less than a day of natural background radiation. It is considered safe, but pregnant women should not have the test.
Preparation
- Wear loose, comfortable clothing without metal zippers, buttons or belts. Or you may be given a gown.
- Skip calcium supplements for 24 hours beforehand, since they can show up in the images.
- Tell the technician if you have had a barium test or contrast imaging in the past 7 to 10 days, or have had spine surgery or metal implants.
- No fasting is needed.
Results
Results are given as a T-score, which compares your bone density with a healthy 30-year-old of the same sex. A T-score of -1.0 or above is normal; between -1.0 and -2.5 means low bone mass (osteopenia); -2.5 or lower means osteoporosis. A Z-score compares you with people of your age. Doctors also use the FRAX tool to estimate the 10-year risk of fracture. Results are usually ready within a few days.
Who needs one
- All women aged 65 and older and men 70 and older, according to guidance of the US Preventive Services Task Force and Bone Health and Osteoporosis Foundation.
- Postmenopausal women and men aged 50 to 69 with risk factors, such as a prior fracture, low body weight, smoking, family history of hip fracture, steroid use or conditions such as rheumatoid arthritis.
- People who have lost more than 1.5 inches of height.
- Those with long-term use of medicines that affect bones.
About 10 million Americans have osteoporosis and 43 million have low bone mass, according to the National Osteoporosis Foundation.
Cost
A DEXA scan costs $100 to $250 without insurance. Medicare covers it every 24 months for those at risk, and most insurers cover it for recommended groups.
DEXA scan details and risk
A bone density scan, known as DEXA or DXA, uses two low dose X-ray beams to measure bone mineral density, usually at the hip and lower spine. The exam takes about 10 to 20 minutes, and the radiation dose is very low at about 1/10th of a chest X-ray, roughly 0.001 millisieverts. Results are given as a T-score: -1.0 or above is normal, between -1.0 and -2.5 indicates low bone mass (osteopenia), and -2.5 or below indicates osteoporosis. The US Preventive Services Task Force recommends screening for women 65 and older and for postmenopausal women under 65 at increased risk. Men over 70 are often screened too. Osteoporosis affects about 10 million Americans, and 44 million more have low bone mass. Do not take calcium supplements for 24 hours before the test, and tell the technician if you recently had a barium or nuclear medicine scan.
Based on data from the Bone Health and Osteoporosis Foundation and the USPSTF
